1. Field of the Invention
This invention relates to an information signal recording and/or reproducing apparatus of the kind using a tape-shaped recording medium and more particularly to an apparatus of that kind capable of accurately detecting a current information signal recording and/or reproducing position on the tape-shaped recording medium.
2. Description of the Related Art
In performing an automatic editing operation with magnetic recording and/or reproducing apparatuses by synchronizing two magnetic tapes which are employed as recording media (hereinafter referred to as tapes), the operation is generally carried out using data indicating the absolute addresses of time codes or the like which are recorded on both the tape used for signal transmission and the tape used for record editing.
The procedures for automatic editing are as follows: A reproducing or searching action or the like is first performed on the transmitting-side tape. A time code Ts for the start point of an image to be recorded by automatic editing is read out. At the same time, another time code Te for the end point of the image to be recorded is also read out. Meanwhile, a reproducing or searching action or the like is performed also on the record-editing-side tape to read out time codes Ts' and Te' for the start and end points of recording. Generally, it suffices to set three of the four time codes Ts, Te, Ts' and Te'.
Next, automatic editing is performed by synchronizing the two tapes on the basis of the time codes Ts, Te, Ts' and Te' to have a desired video signal recorded in a desired place. The automatic editing includes the following steps: The time codes Ts and Ts' which are start points of the two tapes are first read out. Then, the tapes are rewound to an extent corresponding to several frames. A reproducing action is performed on the tapes from the rewound points to the start points. During this process, the two tapes are synchronized. When the two tapes reach the start points, the transmission side is set into a reproducing mode and the record editing side into a recording mode for record editing. Further, when the time codes for the end points are read out, the record editing side is shifted back to the reproducing mode while the transmission side is left in the reproducing mode. Then, after a reproducing process is allowed to continue for several frames, the two tapes are brought to a stop to complete the automatic editing operation.
In most cases, a pre-confirming action is performed to ensure correct setting for automatic editing prior to automatic editing and a post-confirming action to ensure completion of automatic editing. For the pre-confirmation, the record editing side is left in the reproducing mode without being changed to the recording mode while the tapes are allowed to travel in the same manner as in the above-stated automatic editing action. For the post-confirmation, the record editing side is alone caused to act in the same manner as in the automatic editing action although it remains in the reproducing mode without being changed to the recording mode.
For detecting the degree of progress of the automatic editing action, either the time codes which are read out any time as desired are arranged to be displayed as they are, or a lap time from the start point is arranged to be measured and displayed by the apparatus.
The conventional magnetic recording and/or reproducing apparatus has the following shortcomings because of the arrangement to read out and display the time codes recorded on the tape or to display the lap time measured on the side of the apparatus:
It is difficult to instantly find the degree of progress of the automatic editing process within an initially set editing range. It is impossible to find the state of progress of the automatic editing particularly in cases where the time codes are inconsecutive within the set range.
In cases where weight is given to an important part of the tape by slowly moving the part while unimportant parts of the tape are quickly moved either forward or backward, the lap time display is hardly usable as reliable data for judging the degree of progress of the automatic editing operation.